The Museo del Settecente Venez-iano (Museum of the Venetian 18th Century), with its theatrical and richly modelled facade, was begun in 1667 by the great baroque architect Baldassare Longhena. In the mid-18th century it was given an interior of breathtaking sumptuousness by the palace's new and showy owners - the Rezzonicos, one of whom became Pope Clement XIII in 1758. It is this family connection that gave the museum the name by which it is more usually known, the Ca' Rezzonico (Rezzonico House).
Sold off after the fall of the Venetian Republic, the palace briefly belonged to Robert Browning's son; the poet himself caught a cold and died there in 1889. In 1933 the municipality of Venice unwittingly hastened the by now empty building's decline into obscurity, by turning it into a "Museum of the Venetian 18th Century" and placing here the relevant holdings from the Museo Correr.
Part of the blame for this museum's astonishing neglect must lie indirectly with John Ruskin, who encouraged the still widely prevalent notion that Venice went into a moral decline after the Renaissance and thereafter produced works of art of increasing flippancy and emotional dishonesty.
The Ca' Rezzonico, with its extensive original decorations and stupendous views over the Grand Canal, offers an opportunity not only to view this art in the most beautiful and appropriate setting possible, but also to reassess its remarkable range and power.
Among the museum's more gentle surprises are small panel paintings by Pietro Longhi, whose portrayals of the Venetian middle class have often been compared with the plays of his friend Carlo Goldoni. Prevented by the strict censorship of the time from satirising his subjects, he adopted a matter-of-fact naturalism even when painting so extraordinary a subject as a group of carnival revellers witnessing, in 1751, the first public display of a rhinoceros in Europe since the Renaissance.
Genre scenes such as these held much less interest for 18th-century tourists than did detailed topographical views of the city. The one Venetian artist who has been consistently admired by the British is Canaletto. So many of his works ended up in Britain that the only ones that can be seen today in a Venetian public collection are two fine early views recently acquired by the Ca' Rezzonico.
But the artistic greatness of 18th-century Venice rests above all on its painted decorations; and it is these that make a visit to this museum such a special experience. No other palace in Venice open to the public has frescoed ceilings by Giambattista
Tiepolo - the most famous frescoist of the 18th century. His virtuosity was such as to glorify convincingly in paint the dynastic ambitions of his unworthy patrons. Equally astonishing are GB Crosato's magnificently ornamental frescoes covering the palace's enormous ballroom. Their sensual effect is brilliantly enhanced by huge gilded mirrors and the rippling reflections from the Grand Canal.
In complete contrast to all this pal-atial splendour are the frescoes that once decorated Tiepolo's modest family villa near Mira, which have been reassembled in an intimate suite of rooms. Largely executed by Tiepolo's son, Giandomenico, these works were intended to entertain rather than impress; they even have clowns dangling above the spectator.
The visitor returns to the world of propaganda in what is perhaps the museum's most memorable work. Painted originally for the salon of the Palazzo Pisani, this is a late canvas of vast proportions by Giambattista Piazzetta - his dark, dramatically lit and laboriously executed works could hardly be more different from the effortless, serene, pastel-coloured creations of the mature Tiepolo.
This particular painting illustrates the munificence of Alexander the Great, with whom so many Venetian patrons liked to identify: Alexander is shown here removing his cloak to cover up the ignobly exposed corpse of his enemy Darius. But where other Venetian artists, such as Veronese and Tiepolo, would have emphasised the splendour of Alexander's gesture, Piazzetta concentrated instead on the humble state of the defeated Persian emperor in death. Few other works offer so powerful a corrective to the popular image of 18th-century Venice as a shallow and frivolous city.
GETTING TO VENICE: Italy Sky Shuttle (081-748 1333) offers flights to Venice from Gatwick for £144 return until 22 February. Lupus Travel (071-306 3000) provides flights from Manchester to Venice for £154 return. City breaks to Venice are widely available. Italiatour (071-371 1114) provides two nights in a two-star hotel for £263 after 26 February. During the Venice Carnival (14-26 February) the cost rises to £343. Prices will be higher and rooms more difficult to obtain during this period. The Magic ofItaly (081-748 2661) offers three nights in a two-star hotel for £242 from Gatwick until 23 February. Departing from Manchester requires a £20 flight supplement.
GETTING TO THE MUSEUM: Ca' Rezzonico is at Canal Grande, Dorso-duro (tel: 041-24543). Take the No 1 boat (the Accelerato), which follows the whole length of the Grand Canal and stops directly outside the palace. Alter-natively, take the much faster No 2 (the Diretto) from the Piazzale Roma to San Samuel, and from there proceed by public gondola (traghetto) to San Bar-naba. Ca' Rezzonico is open Monday-Thursday and Saturday, 10am-4pm; Sunday, 9am-noon; closed Friday. !